text: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef ASH_APP_LIST_MODEL_APP_LIST_MODEL_H_
  #define ASH_APP_LIST_MODEL_APP_LIST_MODEL_H_
  
  #include <stddef.h>
  
  #include <memory>
  #include <string>
  #include <vector>
  
  #include "ash/app_list/model/app_list_item_list.h"
  #include "ash/app_list/model/app_list_item_list_observer.h"
  #include "ash/app_list/model/app_list_model_export.h"
  #include "ash/public/cpp/app_list/app_list_types.h"
  #include "base/macros.h"
  #include "base/observer_list.h"
  #include "base/scoped_multi_source_observation.h"
  
  namespace ash {
  
  class AppListFolderItem;
  class AppListItem;
  class AppListItemList;
  class AppListModelObserver;
  
  // Main model for the app list. Holds AppListItemList, which owns a list of
  // AppListItems and is displayed in the grid view.
  // NOTE: Currently this class observes |top_level_item_list_|. The View code may
  // move entries in the item list directly (but can not add or remove them) and
  // the model needs to notify its observers when this occurs.
  class APP_LIST_MODEL_EXPORT AppListModel : public AppListItemListObserver {
   public:
    AppListModel();
    ~AppListModel() override;
  
    void AddObserver(AppListModelObserver* observer);
    void RemoveObserver(AppListModelObserver* observer);
  
    void SetStatus(AppListModelStatus status);
  
    void SetState(AppListState state);
    AppListState state() const { return state_; }
  
    // The current state of the AppListView. Controlled by AppListView.
    void SetStateFullscreen(AppListViewState state);
    AppListViewState state_fullscreen() const { return state_fullscreen_; }
  
    // Finds the item matching |id|.
    AppListItem* FindItem(const std::string& id);
  
    // Find a folder item matching |id|.
    AppListFolderItem* FindFolderItem(const std::string& id);
  
    // Adds |item| to the model. The model takes ownership of |item|. Returns a
    // pointer to the item that is safe to use (e.g. after passing ownership).
    AppListItem* AddItem(std::unique_ptr<AppListItem> item);
  
    // Adds |item| to an existing folder or creates a new folder. If |folder_id|
    // is empty, adds the item to the top level model instead. The model takes
    // ownership of |item|. Returns a pointer to the item that is safe to use.
    AppListItem* AddItemToFolder(std::unique_ptr<AppListItem> item,
                                 const std::string& folder_id);
  
    // Add a "page break" item right after the specified item in item list.
    void AddPageBreakItemAfter(const AppListItem* previous_item);
  
    // Merges two items. If the target item is a folder, the source item is
    // added to the end of the target folder. Otherwise a new folder is created
    // in the same position as the target item with the target item as the first
    // item in the new folder and the source item as the second item. Returns
    // the id of the target folder, or an empty string if the merge failed. The
    // source item may already be in a folder. See also the comment for
    // RemoveItemFromFolder. NOTE: This should only be called by the View code
    // (not the sync code); it enforces folder restrictions (e.g. the target can
    // not be an OEM folder).
    const std::string MergeItems(const std::string& target_item_id,
                                 const std::string& source_item_id);
  
    // Move |item| to the folder matching |folder_id| or to the top level if
    // |folder_id| is empty. |item|->position will determine where the item
    // is positioned. See also the comment for RemoveItemFromFolder.
    void MoveItemToFolder(AppListItem* item, const std::string& folder_id);
  
    // Move |item| to the folder matching |folder_id| or to the top level if
    // |folder_id| is empty. The item will be inserted before |position| or at
    // the end of the list if |position| is invalid. Note: |position| is copied
    // in case it refers to the containing folder which may get deleted. See
    // also the comment for RemoveItemFromFolder. Returns true if the item was
    // moved. NOTE: This should only be called by the View code (not the sync
    // code); it enforces folder restrictions (e.g. the source folder can not be
    // type OEM).
    bool MoveItemToFolderAt(AppListItem* item,
                            const std::string& folder_id,
                            syncer::StringOrdinal position);
  
    // Sets the position of |item| either in |top_level_item_list_| or the
    // folder specified by |item|->folder_id(). If |new_position| is invalid,
    // move the item to the end of the list.
    void SetItemPosition(AppListItem* item,
                         const syncer::StringOrdinal& new_position);
  
    // Sets the name of |item| and notifies observers.
    void SetItemName(AppListItem* item, const std::string& name);
  
    // Sets the name and short name of |item| and notifies observers.
    void SetItemNameAndShortName(AppListItem* item,
                                 const std::string& name,
                                 const std::string& short_name);
  
    // Deletes the item matching |id| from |top_level_item_list_| or from the
    // appropriate folder.
    void DeleteItem(const std::string& id);
  
    // Wrapper around DeleteItem() which will also clean up if its parent folder
    // has a single child left.
    void DeleteUninstalledItem(const std::string& id);
  
    // Deletes all items. This is used in profile switches.
    void DeleteAllItems();
  
    AppListItemList* top_level_item_list() { return top_level_item_list_.get(); }
  
    AppListModelStatus status() const { return status_; }
  
   private:
    // AppListItemListObserver
    void OnListItemMoved(size_t from_index,
                         size_t to_index,
                         AppListItem* item) override;
  
    // Returns an existing folder matching |folder_id| or creates a new folder.
    AppListFolderItem* FindOrCreateFolderItem(const std::string& folder_id);
  
    // Adds |item_ptr| to |top_level_item_list_| and notifies observers.
    AppListItem* AddItemToItemListAndNotify(
        std::unique_ptr<AppListItem> item_ptr);
  
    // Adds |item_ptr| to |top_level_item_list_| and notifies observers that an
    // Update occured (e.g. item moved from a folder).
    AppListItem* AddItemToItemListAndNotifyUpdate(
        std::unique_ptr<AppListItem> item_ptr);
  
    // Adds |item_ptr| to |folder| and notifies observers.
    AppListItem* AddItemToFolderItemAndNotify(
        AppListFolderItem* folder,
        std::unique_ptr<AppListItem> item_ptr);
  
    // Removes |item| from |top_level_item_list_| or calls RemoveItemFromFolder
    // if |item|->folder_id is set.
    std::unique_ptr<AppListItem> RemoveItem(AppListItem* item);
  
    // Removes |item| from |folder|. If |folder| becomes empty, deletes |folder|
    // from |top_level_item_list_|. Does NOT trigger observers, calling function
    // must do so.
    std::unique_ptr<AppListItem> RemoveItemFromFolder(AppListFolderItem* folder,
                                                      AppListItem* item);
  
    std::unique_ptr<AppListItemList> top_level_item_list_;
  
    AppListModelStatus status_ = AppListModelStatus::kStatusNormal;
    AppListState state_ = AppListState::kInvalidState;
    // The AppListView state. Controlled by the AppListView.
    AppListViewState state_fullscreen_ = AppListViewState::kClosed;
    base::ObserverList<AppListModelObserver, true> observers_;
    base::ScopedMultiSourceObservation<AppListItemList, AppListItemListObserver>
        item_list_scoped_observations_{this};
    DISALLOW_COPY_AND_ASSIGN(AppListModel);
  };
  
  }  // namespace ash
  
  #endif  // ASH_APP_LIST_MODEL_APP_LIST_MODEL_H_
  